When the bike is idling it will randomly missfire sometimes stalling the bike ao i have to turn the idle speed up and sometimes still misfires. The bike was running lean so i adjusted it and its still doing it. Also when i let off the throttle the bike backfires alot (not loudly) but gurgles.are the valves maybe sticking or valve clearance wrong? please help

SOURCE: bike backfire

Yes, it could (and probably is) be an air leak. Check to be sure the carb is tight in the intake manifold, and make sure the hot-start isn't loose and is sealing properly. Also make sure all of the exhaust system joints are tight, an air leak in the exhaust will make a four-stroke pop and backfire like an old work truck with no muffler...

SOURCE: backfire

Yes, it could (and probably is) be an air leak. Check to be sure the carb is tight in the intake manifold, and make sure the hot-start isn't loose and is sealing properly. Also make sure all of the exhaust system joints are tight, an air leak in the exhaust will make a four-stroke pop and backfire like an old work truck with no muffler...

SOURCE: backfire

Yes, it could (and probably is) be an air leak. Check to be sure the carb is tight in the intake manifold, and make sure the hot-start isn't loose and is sealing properly. Also make sure all of the exhaust system joints are tight, an air leak in the exhaust will make a four-stroke pop and backfire like an old work truck with no muffler...

SOURCE: backfire

Anna14 is right with the air leak,this can also be a misadjusted or faulty throttle position sensor or defective CDI Unit or a lean feul mixture.

SOURCE: 04 crf 250r.... the head has a chattering noise when running

Any chance the valve spring has collapsed? Cam shaft thrust washers missing? Cam shaft bearing gone bad?
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